With the increase in the complexity of RF network systems, mobile devices are often equipped with functions in such a manner that one mobile device can support different types of communication network systems. This has lead to the development of dual mode mobile devices. Dual mode mobile devices or hybrid mobile devices refer to mobile devices that can support at least two or more forms of RF communication technology, i.e., at least two or more RF communication services. Therefore, a user can enjoy a variety of communication services using the dual mode mobile device.
For example, dual mode mobile devices are implemented to support part or all of RF communication network systems, i.e., mobile communication systems, data communication systems, and the like. Examples of the mobile communication systems are Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (W-CDMA), and the like. Examples of the data communication systems are Wireless Local Area Network (WLAN), Wibro, WiFi, High Data Rate (HDR), and the like. In particular, HDR refers to a data communication technology that provides high-speed packet data transmission. HDR optimizes a system in order to transmit packet data at high-speed, so that the system can transfer the data, for example, texts, video, and so forth, at a data transfer rate of up to 2.45 Mbit/sec in a 1.25 MHz channel.
Dual mode mobile devices scan and acquire a mobile communication system using a Preferred Roaming List (PRL), and then scan and acquire a data communication system that has the same association tag as the acquired mobile communication system from the PRL.
However, in a time zone boundary area, i.e., a boundary region between time zones, conventional dual mode mobile devices may acquire a data communication system that uses a local time that differs from a local time used by a currently acquired mobile communication system. In this situation, the conventional dual mode mobile devices may provide incorrect time information to the users. In addition, since conventional dual mode mobile devices acquire a data communication system and a mobile communication system that cannot achieve mutual synchronization, they may malfunction.
Therefore, in a time zone boundary area, a technology is required that avoids scanning and acquiring a data communication system that uses a local time that differs from a local time used by an acquired mobile communication system.